Method to produce a veneered element and a veneered element

ABSTRACT

A method to produce a veneered element, the method including applying a first layer on a substrate, applying a second layer on the first layer, applying a veneer layer on the second layer, pressing the first layer, the second layer and the veneer layer together to form a veneered element, wherein, after pressing, the second layer is transparent or translucent such that the first layer is visible through a crack, cavity, hole and/or knot of the veneer layer. Also, such a veneered element.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of Swedish Application No.1850032-2, filed on Jan. 11, 2018. The entire contents of SwedishApplication No. 1850032-2 are hereby incorporated herein by reference intheir entirety.

TECHNICAL FIELD

The present application relates to a method to produce a veneeredelement, and such a veneered element.

TECHNICAL BACKGROUND

Floor coverings having a wooden surface may be of several differenttypes. Solid wood floorings are formed of a solid piece of wood in formof a plank. Engineered wood floorings are formed of a surface layer ofwood glued to a core. The core may be a lamella core or a wood-basedpanel, such as plywood, MDF or HDF. The wooden surface layer may, as anexample, have a thickness of 2-10 mm.

A wooden floor covering may also be formed by gluing a wood veneer to acore, for example, a wood-based panel, such as particleboard, MDF orHDF. Wood veneer is a thin wood layer, for example having a thickness of0.2-1 mm. A flooring with a separate surface layer glued to a core of,for example, HDF or plywood is more moisture stable than solid woodfloorings.

Compared to solid wood and engineered wood floorings, wood veneerfloorings can be produced to a lower cost since only a thin wood layeris used. However, a wood veneer layer cannot be sanded as a solid woodor engineered wood flooring can be.

As an alternative to wood floorings, laminate floorings are alsoavailable. Direct pressed laminated flooring usually comprises a core ofa 6-12 mm fibre board, a 0.2 mm thick upper decorative surface layer oflaminate and a 0.1-0.2 mm thick lower balancing layer of laminate,plastic, paper or like material.

A laminate surface conventionally comprises two paper sheets; a 0.1 mmthick printed decorative paper and a 0.05-0.1 mm thick transparentoverlay intended to protect the decorative paper from abrasion. Thetransparent overlay, which is made of α-cellulose fibres, comprisessmall hard and transparent aluminium oxide particles, which gives thesurface layer a high wear resistance.

The printed decorative paper and the overlay are impregnated withmelamine resin and laminated to a wood fibre based core under heat andpressure. The two papers have prior to pressing a total thickness ofabout 0.3 mm and they are after pressing compressed to about 0.2 mm.

A wood veneer flooring may have a lower impact resistance than laminatefloorings and the production cost is high, compared to laminatefloorings, when high quality veneers are to be used.

Recently new “paper free” floor types have been developed with a solidsurface comprising a substantially homogenous powder mix of fibres,binders and wear resistant particles. The mix is applied on a wood-basedpanel, such as MDF or HDF, and subsequently heat and pressure areapplied to the mix to form a surface layer on the panel, as disclosed inWO 2009/065769. Such a surface layer is marketed under the trademarkNADURA®.

WO 2009/065769 also discloses a thin surface layer, such as wood veneerlayer, which is applied on a sub-layer comprising, for example, cork orwood fibres mixed with a binder. The sub-layer is applied on wood fibrebased core.

U.S. Pat. No. 2,831,794 discloses a process for manufacturing veneerpanels. A green veneer is applied on a mat of resin coated coreparticles of ligno-cellulose fibrous particles. Adhesive is applied onthe veneer to bond the veneer to the fibrous core, and to form a densesurface zone in the fibrous core. The material of the core serves tofill knot holes or open flaws in the veneer. When heat and pressure areapplied, the result is the formation of a panel, wherein the resincoated core particles fill whatever flaws or holes that would otherwisebe present in the veneer.

U.S. Pat. No. 2,419,614 discloses a coated wood product wherein aplywood is coated by a covering or overlay material consisting ofmixtures of sawdust and synthetic resin. The veneer layer is coated bythe covering or overlay material such that the veneer is no longervisible. The covering forms the uppermost layer of the product.

WO 2015/105455 discloses that holes and cracks of a wood veneer can befilled with material from a sub-layer comprising wood fibres and abinder during pressing. Thereby, a wood veneer of lower quality can beused.

WO 2015/105456 discloses a method of controlling permeation of asub-layer through a wood veneer during pressing. Thereby, the design ofthe wood veneer after pressing can be controlled, by controlling thedegree of permeation of materials from the sub-layer through the woodveneer.

In the above description, the different types of products have beendescribed with reference to floorings. However, the same material andproblems apply for other types of building panels, such as wall panels,ceiling panels, and for furniture components.

SUMMARY

It is an object of at least embodiments of the present invention toprovide an improvement over the above described techniques and knownart.

A further object of at least embodiments of the present invention is toprovide improved designs of veneer layers.

A further object of at least embodiments of the present invention is tofurther control the design of a veneer layer after pressing.

A further object of at least embodiments of the present invention is toprovide a veneer layer with defects, such as holes, cracks and knots,filled with material from a layer arranged below the veneer layerwithout affecting other portions of the veneer layer.

At least some of these and other objects and advantages that will beapparent from the description have been achieved by a method to producea veneered element according to a first aspect of the invention. Themethod comprises applying a first layer on a substrate, applying asecond layer on the first layer, applying a veneer layer on the secondlayer, pressing the first layer, the second layer and the veneer layertogether to a veneered element, wherein, after pressing, the secondlayer is transparent or translucent such that the first layer is visiblethrough a defect, such as a crack, cavity, hole and/or knot, of theveneer layer.

Defect includes any crack, cavity, hole and/knot in the veneer layer. Adefect may include any portion of the veneer layer not being solidand/or dense. Dense portions of the wood veneer are the portions of theveneer layer, where there are no visible by eye defects, i.e.macroscopic defects, such as cracks, cavities, holes and/or knots.

Cracks, cavities, holes and/knots may also be desired and formed duringthe production process, and thus forming desired defects of the veneerlayer.

An advantage of at least embodiments of the first aspect is that thedesign of the veneer layer element can be further controlled by applyingthe veneer layer on two layers having different properties. Theformulation of the first layer may be different from the formulation ofthe second layer. For example, the first layer may be pigmented or dyed,and the second layer may be free from pigments and/or dyes. As anotheralternative, the first layer may have a colour being different from thecolour of the second layer. Thereby, the design of the veneer, afterpressing, can be controlled.

During pressing, material from the second layer permeates at leastpartly into the veneer layer and/or through the veneer layer. The secondlayer, at least partly permeating into the veneer layer, at least partlyor completely prevents the first layer from permeating into or throughthe veneer layer, as compared to an embodiment wherein only a singlelayer is provided.

Permeating means that the second layer is diffuses or penetrates intothe microscopic structure of veneer layer, the structure not visible bythe eye, such as wood pores.

However, in any defect of the veneer layer, such as cracks, holes and/orknots, the first layer is visible through the second layer beingtransparent or at least translucent. Translucent means that the secondlayer allows light but not detailed shapes to pass through,semi-transparent.

Thereby, defects, such as cracks, holes and knots, are visible as iffilled with material from the first layer, as the second layer istransparent or at least translucent. For example, the first layer may becoloured in a darker colour than the colour of the veneer layer.Thereby, defect, such as cracks, holes and knots, are visible as ifcoloured with a dark colour.

Due to the fact that the second layer is transparent or translucent thefirst layer is visible through the defects, such as cracks, cavities,holes and/or knots. Thereby defects are perceived as having a color ofthe first layer, at the same time when the second layer permeates intothe microscopic structure of the veneer layer, thereby at leastpartially preventing permeation of the first layer into themicrostructure of the veneer layer. This creates a visual appearance ofthe veneer layer, which is more aesthetically appealing. For example,when the first layer has a dark color, the transparent or translucentsecond layer at least partially permeates into the veneer layer. Thedark color is visible through the cracks but at least partiallyprevented from permeating into the veneer layer by the second layer.

However, for some designs, it may be undesired to change the design ofthe veneer layer itself by permeating such coloured material throughother portions of the veneer layer than defects, such as through solidparts of the veneer layer, i.e. dense parts of the veneer. By arrangingthe second layer on the first layer, the veneer layer is permeated bythe second layer instead, and the second layer may at least partly orcompletely prevent the first layer from permeating into the veneerlayer. Thereby, the veneer layer, except any defects, may besubstantially unaffected by the first layer after pressing. For example,by using a second layer being substantially free from pigments of dyes,permeation of the second layer through the veneer layer results insubstantially no change of the design of the veneer layer, or at least aless visible change of the design of the veneer layer. Thereby, defects,such as knots, holes and cracks, are visible as if filled with materialhaving one colour, and the rest of the veneer layer remainssubstantially unaffected.

As another example, the second layer may have different colour than thefirst layer, such that any defect, such as a knot, hole and crack, hasone colour (primarily from the first layer) and material permeating intothe veneer layer has another colour (primarily from the second layer).Thereby, the veneer layer may be stained in one colour (primarily fromthe second layer), for example with a light colour or a colourcorresponding to a natural colour of the veneer layer, and defects, suchas knots, holes and cracks, may have a different colour after pressing,for example a dark colour (primarily from the first layer).

The veneer layer may be or comprise a wood veneer or a cork veneer.

During pressing, a crack, hole and/or knot of the veneer layer may be atleast partially filled with material originating from at least thesecond layer, preferably with material from originating both the firstand the second layer. Preferably, the material filling defect, such as acrack, hole and/or knot, is flush with an upper surface of the veneerlayer after pressing.

During pressing, material originating from the second layer may permeateinto the veneer layer. That is, permeating into the material of theveneer, as opposed to filling in a defect. The material originating fromthe second layer may permeate into the veneer layer and/or through theveneer layer.

During pressing, the second layer may prevent material originating fromthe first layer from permeating into and/or through the veneer layer.Thereby, the veneer layer, except any defects, may remain substantiallyunaffected by material originating from the first layer after pressing.

The first layer may comprise pigments and/or dyes.

The first layer may have a substantially uniform colour. The first layermay be substantially uniformly coloured over its horizontal extension.The first layer may be substantially uniformly coloured in its verticalextension.

The second layer may have a substantially uniform colour. The secondlayer may be substantially uniformly coloured over its horizontalextension. The second layer may be substantially uniformly coloured inits vertical extension.

The second layer may be free from pigments and dyes. After pressing, thesecond layer is transparent, or at least translucent.

The second layer may have a different colour than the first layer afterpressing. The second layer may stain the veneer layer after pressing.The second layer may comprise pigments and/or dyes.

The first layer may comprise a thermosetting binder. The thermosettingbinder may be an amino resin, for example, melamine formaldehyde, ureaformaldehyde, or a combination or co-polymer thereof.

The second layer may comprise a thermosetting binder. The thermosettingbinder may be an amino resin, for example, melamine formaldehyde, ureaformaldehyde, or a combination or co-polymer thereof.

In one embodiment, the first layer and/or the second layer may comprisea thermoplastic binder. The first layer and/or the second layer maycomprise a thermoplastic foil.

The first layer may be applied as a dry powder. For example, the binderof the first layer may be applied as a dry powder. Alternatively, thefirst layer may be applied in liquid form, for example by applying thebinder in liquid form.

The second layer may be applied as a dry powder. For example, the binderof the second layer may be applied as a dry powder. Alternatively, thesecond layer may be applied in liquid form, for example by applying thebinder in liquid form.

The second layer may be applied in an amount of at least 100 g/m2. Byapplying at least 100 g/m2, the second layer may prevent the first layerfrom permeating into the veneer layer during pressing. The amountrequired to prevent the first layer from permeating into the veneerlayer during pressing is also dependent on properties the veneer layer,such as the thickness of the veneer layer.

The first and/or the second layer may further comprise fillers. Thefillers may be particles or fibres, for example wood fibres orparticles, or mineral particles or fibres. The wood particles may belignocellulosic particles and/or cellulosic particles. The woodparticles may be at least partially bleached.

The first and/or the second layer may comprise wear resistant particlesand/or scratch resistant particles. Preferably, at least the secondlayer comprises wear resistant particles and/or scratch resistantparticles.

The first layer and/or the second layer may comprise a paper sheet,preferably a resin impregnated paper sheet. In an embodiment wherein thefirst layer comprises a paper sheet, the paper sheet may be coloured. Inan embodiment wherein the second layer comprises a paper sheet, thepaper sheet may be an overlay sheet, for example of the type used forlaminate flooring. After pressing, such an overlay sheet is transparent.

The first layer may comprise a layer of paint, such as any commerciallyavailable paint suitable for the purpose.

The substrate may comprise a wood-based board such MDF, HDF,particleboard, a thermoplastic board, a plywood, a lamella core, aveneer layer, such as a wood veneer or cork veneer, a sheet, such aspaper sheet, a non-woven, or a conveyor. In one embodiment, thesubstrate may be included in the veneered element after pressing, bypressing, the substrate, the first layer, the second layer and theveneer layer together. In one embodiment, the veneered element may beremoved from the substrate after pressing.

According to a second aspect of the present invention, a veneeredelement is provided. The veneered element comprises a substrate, a firstlayer arranged on the substrate, a second layer arranged on the firstlayer, wherein the second layer is transparent or translucent, and aveneer layer arranged on the second layer, wherein the first layer isvisible through a hole, crack and/or knot of the veneer layer.

Embodiments of the second aspect of the present invention mayincorporate all the advantages of the first aspect of the invention,which previously has been discussed, whereby the previous discussion isapplicable also for the veneered element.

The veneer layer may be or comprise a wood veneer or a cork veneer.

The crack, hole and/or knot of the veneer layer may be at leastpartially filled with material originating from at least the secondlayer, preferably with material from originating both the first and thesecond layer. Preferably, the material filling a defect, such as acrack, hole and/or knot is flush with an upper surface of the veneerlayer.

The second layer may be adapted to prevent material originating from thefirst layer from permeating into and/or through the veneer layer.Thereby, the veneer layer, except any defects, may remain substantiallyunaffected by material from the first layer after pressing.

Material originating from the second layer may be present in the veneerlayer.

The first layer may comprise pigments and/or dyes.

The first layer may have a substantially uniform colour. The first layermay be substantially uniformly coloured over its horizontal extension.The first layer may be substantially uniformly coloured in its verticalextension.

The second layer may have a substantially uniform colour. The secondlayer may be substantially uniformly coloured over its horizontalextension. The second layer may be substantially uniformly coloured inits vertical extension.

The second layer may be free from pigments and dyes.

The second layer may have a different colour than the first layer afterpressing. The second layer may stain the veneer layer after pressing.

The first layer may comprise a thermosetting binder. The thermosettingbinder may be an amino resin, for example, melamine formaldehyde, ureaformaldehyde, or a combination or co-polymer thereof.

The second layer may comprise a thermosetting binder. The thermosettingbinder may be an amino resin, for example, melamine formaldehyde, ureaformaldehyde, or a combination or co-polymer thereof.

In one embodiment, the first layer and/or the second layer may comprisea thermoplastic binder.

The first and/or the second layer may further comprise fillers. Thefillers may be particles or fibres, for example wood fibres orparticles, or mineral particles or fibres. The wood particles may belignocellulosic particles and/or cellulosic particles. The woodparticles may be at least partially bleached.

The first and/or the second layer may comprise wear resistant particlesand/or scratch resistant particles. Preferably, at least the secondlayer comprises wear resistant particles and/or scratch resistantparticles.

The first layer and/or the second layer may comprise a paper sheet,preferably a resin impregnated paper sheet. In an embodiment wherein thefirst layer comprises a paper sheet, the paper sheet may be coloured. Inan embodiment wherein the second layer comprises a paper sheet, thepaper sheet may be an overlay sheet, for example of the type used forlaminate flooring. After pressing, such an overlay sheet is transparent.

The substrate may comprise a wood-based board, such as MDF, HDF,particleboard, a thermoplastic board, a plywood, a lamella core, aveneer layer, such as a wood veneer or cork veneer, a sheet, such aspaper sheet, a non-woven, or a conveyor. In one embodiment, thesubstrate may be included in the veneered element after pressing, bypressing, the substrate, the first layer, the second layer and theveneer layer together. In one embodiment, the veneered element may beremoved from the substrate after pressing.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will by way of example be describedin more detail with reference to the appended schematic drawings, whichshow embodiments of the present invention.

FIGS. 1A-1B illustrates a method of a producing a veneered elementaccording to an embodiment.

FIG. 2 illustrates a cross-section of an embodiment of a veneeredelement.

FIG. 3 illustrates an embodiment of a veneered element.

DETAILED DESCRIPTION

FIGS. 1A-1B show a method of producing a veneered element 10. Theveneered element 10 may be a furniture component, a building panel, suchas a floor panel, a ceiling panel, a wall panel, a door panel, aworktop, skirting boards, mouldings, edging profiles, etc. The methodcomprises providing a substrate 1. The substrate 1 is preferably apre-fabricated substrate, manufactured prior to the method of producingthe veneered element 10. The substrate 1 may be a board, for example, awood-based board as shown in the embodiment shown in FIGS. 1-3. Thewood-based board may be a wood fibre based board, such as MDF, HDF,particleboard, etc., or a plywood board. In other embodiments, thesubstrate 1 may be a Wood Plastic Composite (WPC). The substrate 1 maybe a mineral composite board. The substrate 1 may be a fibre cementboard. The substrate 1 may be magnesium oxide cement board. Thesubstrate 1 may be a ceramic board. The substrate 1 may be a plasticboard, such as a thermoplastic board. In another embodiment, thesubstrate 1 may be a carrier, such as sheet of paper, a veneer layer, ornon-woven, or a conveyor. The carrier may be a resin impregnated sheet,such as a resin impregnated paper.

In FIG. 1A, a first layer 2 a is applied on a first surface of thesubstrate 1. In the embodiment shown in FIG. 1A, the first layer 2 a isapplied in powder form 21. The powder 21 adapted to form the first layer2 a is applied by scattering, as shown in FIG. 1A, for example by ascattering device 20. Powders are finely divided chemicals in a dryform, more precisely subdivided solids containing constituent individualparticles.

The first layer 2 a may also be applied as granules. In the context ofpresent invention granules are typically understood as aggregation offine particles to form larger particles. In other embodiments, the firstlayer 2 a may be applied as a liquid, as a paste, a sheet, etc. Thefirst layer 2 a may be applied by roller coating, spraying, etc.

In one embodiment (not shown), the first layer 2 a comprises a sheetimpregnated with a thermosetting binder. The sheet may be paper sheet.The sheet may be coloured, and/or the binder solution used to impregnatethe sheet may be coloured, such that sheet becomes coloured duringimpregnation.

The first layer 2 a comprises pigments and/or dyes. Preferably, pigmentsand/or dyes may be darker than the natural colour of the veneer layerwhich is to be applied later in the process. The first layer 2 a haspreferably a uniform colour. The first layer 2 a is preferably uniformlycoloured in the horizontal direction. The first layer 2 a is preferablyuniformly coloured in the vertical direction.

A second layer 2 b is applied on the first layer 2 a. In the embodimentshown in FIG. 1A, the second layer 2 b is applied in powder form 23. Thepowder 23 adapted to form the second layer 2 b is applied by scattering,as shown in FIG. 1A, for example by a scattering device 22. The secondlayer 2 b may also be applied as granules. In other embodiments, thesecond layer 2 b may be applied as a liquid, as a paste, a sheet, etc.The second layer 2 b may be applied by roller coating, spraying, etc.

Moisture may be applied to the first layer 2 a prior to applying thesecond layer 2 b. The first layer 2 a may be dried, for example, byapplying IR or NIR. Moisture may be applied to the second layer 2 b. Thesecond layer 2 b may be dried, for example, by applying IR or NIR.

In one embodiment, the second layer 2 b comprises a sheet impregnatedwith a thermosetting binder. The sheet may be paper sheet. The papersheet may be an overlay paper impregnated with a thermosetting binder asconventionally used in laminate flooring. After pressing, such anoverlay paper will be transparent, or at least translucent.

In one embodiment, the first layer 2 a comprises a sheet impregnatedwith a thermosetting binder as described above, and the second layer 2 bis applied in powder form.

In one embodiment, the first layer 2 a is formed by a layer of paintapplied on the upper surface of the substrate 1, and the second layer 2b is applied in powder form.

In one embodiment, the second layer 2 b is free from pigments and dyes.The second layer 2 b may be uncoloured.

In one embodiment, the second layer 2 b comprises pigments and/or dyes.The colour of the second layer 2 b may be different from the colour ofthe first layer 2 a. The colour of the second layer 2 b may be adaptedto stain the veneer layer later arranged thereon.

The first layer 2 a and the second layer 2 b may comprise a binder. Thebinder may be a thermosetting binder, a thermoplastic binder, or acombination thereof. The binder may be wood mastic, wood filler, or anyother type of putty-like paste. The thermosetting binder may be an aminoresin, such as melamine formaldehyde resin, phenol formaldehyde resin,urea formaldehyde resin, or a combination thereof. Urea formaldehyderesin may be used, alone or in combination with melamine formaldehyderesin, to reduce tension formed by the first layer 2 a and/or the secondlayer 2 b during curing, compared to when melamine formaldehyde resin isused only. The thermoplastic binder may be polyvinyl chloride (PVC),polyethylene (PE), polypropylene (PP), polyurethane (PU), polyvinylalcohol (PVOH), polyvinyl butyral (PVB), polyvinyl acetate (PVAc),and/or thermoplastic elastomer (TPE), or a combination thereof.

The binder described above may be in powder form when applied.

In one embodiment, the first layer 2 a comprises urea formaldehyderesin, and the second layer comprises melamine formaldehyde resin.Melamine formaldehyde resin flows more than urea formaldehyde resin,which may result in permeation, but gives good transparency.

In one embodiment, the second layer 2 b comprises urea formaldehyderesin, and the first layer 2 a comprises melamine formaldehyde resin.Urea formaldehyde resin flows less than melamine formaldehyde resin. Inorder to improve the transparency of the urea formaldehyde resin, thebinder may be applied in liquid form.

In one embodiment, both the first and the second layer comprise ureaformaldehyde resin.

The first layer 2 a and/or the second layer 2 b may be formed of a mixcomprising a binder of the above described type and fillers. The mix mayfurther comprise pigments as described above. The mix may furthercomprise additives. The mix may further comprise wear and/or scratchresistant particles. As an alternative to a mix, the binder, fillers,pigments, additives and any other component may be applied separately onthe substrate 1.

The fillers may be particles or fibres, for example wood fibres orparticles, or mineral particles or fibres. The wood particles may belignocellulosic particles and/or cellulosic particles. The woodparticles may be at least partially bleached. The fillers may be rice,straw, corn, jute, linen, flax, cotton, hemp, bamboo, bagasse or sisalparticles or fibres. The first and/or the second layer 2 a, 2 b maycomprise starch, such as maize starch, potato starch, etc.

If the second layer 2 b comprise wood fibres or particles, the fibres orparticles are preferably at least partially bleached.

The fillers may be fillers having sound-absorbing properties, such ascork particles and/or barium sulphate (BaSO4).

The additives may be wetting agents, anti-static agents, such as carbonblack, and heat-conducting additives, such as aluminium. Other possibleadditives are magnetic substances.

The first layer 2 a and/or the second layer 2 b may also comprise a foilor a sheet.

Additives, such as blowing agents, may be included in the first and/orsecond layers 2 a, 2 b. The blowing agents may be physical foamingagents, such as EXPANCEL®, and/or chemical blowing agents, such as AIBN(azoisobutyronitrile) or ADC (azodicarbonamide).

In one embodiment wherein the second layer 2 a comprises a resinimpregnated sheet of the type described above, the first layer mayinclude blowing agents to improve filling of crack, cavities, holesand/or knots.

The wear and/or scratch resistant particles may be aluminium oxideparticles and/or silica particles.

In one embodiment, the first layer 2 a and/or the second layer 2 bconsists essentially of the binder and optionally additives, meaningthat at least 90 wt % of the first and/or second layer 2 a, 2 b is thebinder and optional additive(s). In one embodiment, the first layer 2 aand/or the second layer 2 b is free from any fibres and/or fillers.

Additives may be, but not limited to, wetting agents, anti-staticagents, such as carbon black, heat conductive additives such asaluminum, magnetic substances; blowing agents, such as physical foamingagents (for example EXPANCEL® or chemical blowing agents such as AIBN(azoisobutyronitrile) or ADC (azodicarbonamide); catalysts.

The first layer 2 a may be applied in an amount of 100-300 g/m2,preferably 150-250 g/m2, such as about 200 g/m2. The amount of binderapplied for the first layer 2 a may be 50-150 g/m2, preferably 75-125g/m2, such as about 100 g/m2. The first layer 2 a may comprise thebinder in an amount of 30-80 wt %, preferably in an amount of 40-60 wt%, such as about 50 wt %.

The second layer 2 b may be applied in an amount of 100-300 g/m2,preferably 150-250 g/m2, such as about 200 g/m2. The amount of binderapplied for the second layer 2 b may be 50-150 g/m2, preferably 75-125g/m2, such as about 100 g/m2. The second layer 2 b may comprise thebinder in an amount of 30-80 wt %, preferably in an amount of 40-60 wt%, such as about 50 wt %.

Preferably, the second layer 2 b is applied in an amount of at least 100g/m2. Preferably, in order to prevent the first layer 2 a frompermeating into the veneer layer 3 during pressing, the second layer 2 bis applied in an amount of at least 200 g/m2.

The first layer 2 a may be pre-pressed prior to applying the secondlayer 2 b. The second layer 2 b may be pre-pressed prior to applying theveneer layer.

In FIG. 1B, a veneer layer 3 has been applied to the second layer 2 b.The veneer layer 3 may be a wood veneer or a cork veneer. The veneer hasa porous structure, thus being permeable. The veneer layer 3 may have athickness of about 0.2 to 1 mm. The veneer layer 3 may be continuous ornon-continuous. The veneer layer 3 may be formed of several veneerpieces. The veneer pieces may be over-lapping or non-overlapping. A gapmay be formed between the veneer pieces.

The veneer layer 3 may comprise defects 6, such as holes, knots and/orcracks. By defects are meant both naturally occurring defects in theveneer, such as holes, cavities, knots and/or cracks, and defects, suchas holes, cavities, knots and/or cracks formed by, for example, abrasivemachining, punching, tearing, brushing, stretching, etc. prior topressing.

A balancing layer may also be applied on a lower surface of the core.The balancing layer 5 may be a powder based balancing layer beingapplied as a powder. The powder based balancing layer may comprise woodparticles, such as lignocellulosic and/or cellulosic particles and abinder, preferably a thermosetting binder, such as an amino resin. Thebalancing layer may be a resin impregnated paper, preferably impregnatedwith a thermosetting binder. The balancing layer may comprise a veneerlayer, such as a wood veneer or cork veneer. The balancing layer maycomprise a veneer layer, such as wood veneer or cork veneer, arranged ona sub-layer comprising wood particles, such as lignocellulosic and/orcellulosic particles, and a binder, preferably a thermosetting binder,such as an amino resin.

As shown in FIG. 1B, when the veneer layer 3 is arranged on the secondlayer 2 b, pressure is applied to the veneer layer 3 and/or thesubstrate 1. The pressure may be applied by continuous press 30 or in adiscontinuous press (not shown). Preferably, heat is also applied.

After pressing, a veneered element 10 is formed, as shown in FIGS. 2 and3. In one embodiment, the veneer layer 3, the first and second layers 2a, 2 b, and the substrate 1 are pressed together such that the veneeredelement 10 includes the substrate 1. In other embodiments, the veneeredelement 10 is removed from the substrate 1 after pressing.

After pressing, the second layer 2 b is transparent or at leasttranslucent. The second layer 2 b may be coloured or stained, butremaining at least translucent. The second layer 2 b may be transparentafter pressing by having a high binder content. If the second layer 2 bcomprises wood fibres or particles, the wood fibres or particles arepreferably cellulosic fibres or particles. The wood fibres or particlesare preferably at least partially bleached.

During pressing, material from the second layer 2 b may permeate throughthe veneer layer 3. Material from the second layer 2 b may permeatepartially through the veneer layer 3 or completely through the veneerlayer 3.

After pressing, defects 6, such as holes, knots and cracks, are filledwith material from at least the second layer 2 b, as shown in FIGS. 2and 3. Preferably, defects 6, such as holes, knots and cracks, arefilled with material from both the first layer 2 a and the second layer2 b. Preferably, material from the second layer 2 b, or from the firstand the second layer 2 a, 2 b, is flush with an upper surface 4 of theveneer layer 3.

During pressing, the second layer 2 b, arranged on the first layer 2 a,prevents the first layer 2 a from at least from completely permeatingthrough the veneer layer 3. Thereby, the veneer layer 3 remainssubstantially unaffected by the first layer 2 a. However, at defects 6of the veneer layer 3, such as holes, knots and cracks, the first layer2 a is visible through the transparent or translucent second layer 2 b.Thereby, it is possible to obtain a visible design of the veneer layer 3wherein defects 6, such as holes, knots and cracks, of the veneer layerare coloured into a darker colour than the rest of the veneer layer 3.The rest of the veneer layer remains substantially unaffected by thefirst layer 2 a, such that the veneer layer 3 is not coloured by thefirst layer 2 a. By substantially unaffected is meant compared to how anappearance the veneer layer 3 would have after pressing if beingarranging on the first layer 2 a only.

In one embodiment, the second layer 2 b is free from any pigments and/ordyes. Thereby, the veneer layer 3 is not coloured by any pigments ordyes from the second layer 2 b after pressing. The veneer layer 3 willonly be affected by, for example by the binder of the second layer 2 b.After pressing, the veneer layer 3 has its original appearance, or atleast substantially its original appearance, while any defects 6, suchas knots, holes and cracks, will be visible as being filled withmaterial having the colour of the first layer 2 a.

In one embodiment, the second layer 2 b comprises pigments and/or dyes.Preferably, the colour of the second layer 2 b is different from thecolour of the first layer 2 a. Thereby, dense parts of the veneer layer3 may be coloured by one colour after pressing by the permeation of thesecond layer 2 b during pressing, while any defects 6, such as knots,holes and cracks, will be visible as being coloured in a differentcolour, due to the first layer 2 a being visible through the transparentor translucent second layer 2 b.

Depending on several parameters, such as binder concentration in thefirst and second layers 2 a, 2 b, moisture content in the first andsecond layers 2 a, 2 b, pressure applied, gas pressure and fillerconcentration in the first and second layers 2 a, 2 b, and depending onthe thickness of the veneer layer, permeation of the first and thesecond layer 2 a, 2 b can be controlled. By controlling theseparameters, the degree of permeation of the first layer 2 a and/or thesecond layer 2 b through the veneer layer can be controlled.

For example, in one embodiment wherein the first layer 2 a comprisesurea formaldehyde as the binder, and the second layer 2 b comprises ureaformaldehyde as the binder, the first layer 2 a is prevented frompermeating through the veneer layer 3 by the second layer 2 b. Thereby,after pressing, the dense parts of the veneer layer 3 remains unaffectedfrom permeation of material from the first layer 2 a.

In one embodiment wherein the first layer 2 a comprises ureaformaldehyde resin as the binder, and the second layer 2 b comprisesmelamine formaldehyde as the binder, the first layer 2 a is notcompletely prevented from permeating through the veneer layer 3 by thesecond layer 2 b. In this embodiment, some material from the first layer2 a may permeate through the veneer layer 3, due to the melamineformaldehyde resin of the second layer 2 b flowing more compared to ureaformaldehyde resin during pressing.

In the embodiment shown in FIGS. 2 and 3, a balancing layer 5 isprovided on a lower surface 9 of the substrate 1. A balancing layer 5may also be applied on a lower surface of a core. The balancing layer 5may be a powder based balancing layer being applied as a powder. Thepowder based balancing layer may comprise wood particles, such aslignocellulosic and/or cellulosic particles, and a binder, preferably athermosetting binder, such as an amino resin. The balancing layer 5 maybe a resin impregnated paper, preferably impregnated with athermosetting binder. The balancing layer 5 may comprise a veneer layer,such as a wood veneer or cork veneer. The balancing layer 5 may comprisea veneer layer such as wood veneer or cork veneer arranged on asub-layer comprising wood particles, such as lignocellulosic and/orcellulosic particles, and a binder, preferably a thermosetting binder,such as an amino resin.

In the embodiment shown in FIGS. 2 and 3, the substrate 1 is a board,such as a wood-based board, a particleboard, a thermoplastic board, aplywood, a lamella core, etc. In other embodiments, the substrate may bea sheet, such as paper sheet, a non-woven, or a veneer layer, such as awood veneer layer or a cork veneer layer.

Furthermore, a protective layer (not shown) may be applied to the veneerlayer 3. The protective layer may be a coating, such as one or severallacquer layers. The coating may be an acrylate or methacrylate coating,such as polyurethane coating. The coating may comprise wear and/orscratch resistant particles. The protective layer may be an overlaypaper comprising wear resistant particles. The protective layer may be apowder overlay, as described in WO 2011/129755, comprising processedwood fibres, a binder and wear resistant particles applied as mix on theveneer surface. If the protective layer comprises or is an overlay paperor a powder overlay, the protective layer is preferably applied beforethe step of applying heat and pressure. Thereby, the protective layer iscured and attached to the veneer layer in the same step as attaching theveneer layer 3 to the first and second layers 2 a, 2 b and to thesubstrate 1.

The veneered element 10 may further be treated in different ways, forexample brushed, oiled, lacquered, waxed, etc.

A protective coating (not shown) may also be applied to the veneer layer3 prior to pressing. In one embodiment, a wax powder is applied, forexample, scattered, on the upper surface of the veneer layer, facingaway from the substrate 1, prior to pressing. During pressing, the waxpowder forms a protective coating of the veneered element 10.

A protective foil (not shown) may also be applied on the veneer layer 3prior or after pressing. The protective coating is applied such that itfaces away from the substrate 1. The protective foil may bethermoplastic foil, such as PU or PVC foil.

In the figures, the first layer 2 a and the second layer 2 b are shownas two separate layers. However, after pressing, the first layer 2 a andthe second layer 2 b may flow into each other such that no borderbetween the layers exists.

It is contemplated that there are numerous modifications of theembodiments described herein, which are still within the scope of theinvention as defined by the appended claims. When the word “about” isused in this specification in connection with a numerical value, it isintended that the associated numerical value include a tolerance of+/−10% around the stated numerical value.

EXAMPLES Example 1

200 g/m2 of a powder composition comprising a mixture of wood powder,melamine formaldehyde resin, starch and white pigment was scattered on aHDF board for forming a first layer. 200 g/m2 of a powder compositioncomprising a mixture of wood powder, melamine resin and aluminium oxidebut no pigments were scattered on top of the first layer for forming asecond layer. The powder layers were stabilized by spraying a watersolution over the surface and drying with IR-heating.

A 0.6 mm oak veneer was positioned on top of the HDF board, the firstand the second powder layers facing each other.

The HDF board and veneer was heat pressed at 170° C. for 35 secondsusing a pressing force of 40 bars, resulting in a panel where the whitepowder composition was visible in the large holes and cracks of theveneer through the second layer, whereas tiny cracks and pores of theveneer where not colored.

Example 2

200 g/m2 of a powder composition comprising a mixture of wood powder,melamine resin, starch and white pigment was scattered on a HDF boardfor forming a first layer. The powder layer was stabilized by spraying awater solution over the surface and drying with IR-heating.

A resin impregnated paper (overlay AC 3), being free from any pigment,was positioned on top of the HDF board for forming a second layer,wherein the first and the second layers are facing each other.

A 0.6 mm oak veneer was positioned on top of the HDF board, the twodifferent powders facing each other, such that the first and the secondlayer are positioned between the HDF board and the oak veneer.

The HDF board and veneer was heat pressed at 160° C. for 35 secondsusing a pressing force of 60 bars, resulting in a panel where the whitepowder composition was visible in the large holes and cracks through thesecond layer, whereas tiny cracks and pores of the veneer where notcolored.

Example 3

375 g/m2 of a powder composition comprising a mixture of wood powder,melamine resin, starch and black pigment was scattered on a HDF boardfor forming a first layer.

150 g/m2 of a powder composition comprising a mixture of wood powder,melamine resin and aluminium oxide but no pigments were scattered on topof the first layer for forming a second layer.

The powder layers were stabilized by spraying a water solution over thesurface and drying with IR-heating.

A 0.6 mm oak veneer was positioned on top of the HDF board, the firstand the second powder layers facing each other, such that the first andthe second layer are positioned between the HDF board and the oakveneer.

The HDF board and veneer was heat pressed at 170° C. for 35 secondsusing a pressing force of 40 bars, resulting in a panel where the blackpowder composition was visible in the large holes and cracks of theveneer through the second layer, whereas tiny cracks and pores of theveneer where not colored.

Example 4

400 g/m2 of a powder composition comprising a mixture of wood powder,urea-formaldehyde resin, inorganic filler, black, white, red, and yellowpigments was scattered on a HDF board for forming a first layer.

150 g/m2 of a powder composition comprising a mixture of wood powder,melamine resin and aluminium oxide but no pigments were scattered on topof the first layer for forming a second layer.

The powder layers were stabilized by spraying a water solution over thesurface and drying with IR-heating.

A 0.6 mm oak veneer was positioned on top of the HDF board, the firstand the second powder layers facing each other, such that the first andthe second layer are positioned between the HDF board and the oakveneer.

The HDF board and veneer was heat pressed at 160° C. for 35 secondsusing a pressing force of 40 bars, resulting in a panel where the beigepowder composition was visible in the large holes and cracks of theveneer through the second layer, whereas tiny cracks and pores of theveneer where not colored.

Example 5

375 g/m2 of a powder composition comprising a mixture of wood powder,melamine resin, starch and black pigment was scattered on a HDF boardfor forming a first layer.

150 g/m2 of a powder composition comprising a mixture of wood powder,melamine resin, urea-formaldehyde resin, starch and aluminium oxide butno pigments were scattered on top of the first layer for forming asecond layer.

The powder layers were stabilized by spraying a water solution over thesurface and drying with IR-heating.

A 0.6 mm oak veneer was positioned on top of the HDF board, the firstand the second powder layers facing each other, such that the first andthe second layer are positioned between the HDF board and the oakveneer.

The HDF board and veneer was heat pressed at 160° C. for 35 secondsusing a pressing force of 40 bars, resulting in a panel where the blackpowder composition was visible in the large holes and cracks of theveneer through the second layer, whereas tiny cracks and pores of theveneer where not coloured.

EMBODIMENTS

1. A method to produce a veneered element, the method comprising

applying a first layer on a substrate,

applying a second layer on the first layer,

applying a veneer layer on the second layer, and

pressing the first layer, the second layer and the veneer layer togetherto form a veneered element,

wherein, after pressing, the second layer is transparent or translucentsuch that the first layer is visible through a defect of the veneerlayer such as a crack, cavity, hole and/or knot.

2. A method according to embodiment 1, wherein, during pressing, anydefect of the veneer layer such as a crack, cavity, hole and/or knot isat least partially filled with material originating from at least thesecond layer, preferably with material from originating both the firstand the second layer.

3. A method according to embodiment 1 or 2, wherein, during pressing,material originating from the second layer permeates into the veneerlayer.

4. A method according to any one of the preceding embodiments, wherein,during pressing, the second layer prevents material originating from thefirst layer from permeating into the veneer layer.

5. A method according to any one of the preceding embodiments, whereinthe first layer comprises pigments and/or dyes.

6. A method according to any one of the preceding embodiments, whereinthe first layer has a substantially uniform colour.

7. A method according to any one of the preceding embodiments, whereinthe second layer is free from pigments and dyes.

8. A method according to any one of embodiments 1-6, wherein, afterpressing, the second layer has a different colour than the first layer.

9. A method according to any one of the preceding embodiments, whereinthe first layer comprises a thermosetting binder.

10. A method according to any one of the preceding embodiments, whereinthe second layer comprises a thermosetting binder.

11. A method according to any one of preceding embodiments, wherein thefirst layer is applied as a dry powder.

12. A method according to any one of the preceding embodiments, whereinthe second layer is applied as a dry powder.

13. A method according to any one of embodiments 1-10, wherein the firstlayer and/or the second layer comprises a paper sheet, preferably aresin impregnated paper sheet.

14. A method according to any one of the preceding embodiments, whereinthe substrate comprises comprise a wood-based board, a particleboard, athermoplastic board, a plywood, a lamella core, a veneer layer, a sheet,or a non-woven.

15. A veneered element, comprising

a substrate,

a first layer arranged on the substrate,

a second layer arranged on the first layer, wherein the second layer istransparent or translucent, and

a veneer layer arranged on the second layer, wherein the first layer isvisible through a defect of the veneer layer, such as a crack, cavity,hole and/or knot.

16. A veneered element according to embodiment 15, wherein the defect ofthe veneer layer is at least partially filled with material originatingfrom at least the second layer, preferably with material fromoriginating both the first and the second layer.

17. A veneered element according to embodiment 15 or 16, whereinmaterial originating from the second layer is present in the veneerlayer.

18. A veneered element according to any one of embodiment 15-17, whereinthe second layer is adapted to prevent material originating from thefirst layer from permeating into the veneer layer.

19. A veneered element according to any one of embodiment 15-18, whereinthe first layer comprises pigments and/or dyes.

20. A veneered element according to any one of embodiment 15-16, whereinthe first layer has a substantially uniform colour.

21. A veneered element according to any one of embodiment 15-20, whereinthe second layer is free from pigments and dyes.

22. A veneered element according to any one of embodiment 15-20, whereinthe second layer has a different colour than the first layer.

23. A veneered element according to any one of embodiments 15-22,wherein the substrate comprises a wood-based board, a particleboard, athermoplastic board, a plywood, a lamella core, a veneer layer, a sheet,or a non-woven.

The invention claimed is:
 1. A method to produce a veneered element, themethod comprising applying a first layer on a substrate, applying asecond layer on the first layer, applying a veneer layer on the secondlayer, and pressing the first layer, the second layer and the veneerlayer together to form a veneered element, wherein, after pressing, thesecond layer is transparent or translucent such that the first layer isvisible through a defect of the veneer layer, wherein both the first andsecond layer comprise a binder.
 2. The method according to claim 1,wherein, during pressing, any defect of the veneer layer is at leastpartially filled with material originating from at least the secondlayer.
 3. The method according to claim 1, wherein, during pressing,material originating from the second layer permeates into the veneerlayer.
 4. The method according to claim 1, wherein, during pressing, thesecond layer prevents material originating from the first layer frompermeating into the veneer layer.
 5. The method according to claim 1,wherein the first layer comprises pigments and/or dyes.
 6. The methodaccording to claim 1, wherein the first layer has a substantiallyuniform colour.
 7. The method according to claim 1, wherein the secondlayer is free from pigments and dyes.
 8. The method according to claim1, wherein, after pressing, the second layer has a different colour thanthe first layer.
 9. The method according to claim 1, wherein the firstlayer comprises a thermosetting binder.
 10. The method according toclaim 1, wherein the second layer comprises a thermosetting binder. 11.The method according to claim 1, wherein the first layer is applied as adry powder.
 12. The method according to claim 1, wherein the secondlayer is applied as a dry powder.
 13. The method according to claim 1,wherein the first layer or the second layer comprises a paper sheet. 14.The method according to claim 13, wherein the first layer and the secondlayer comprise a paper sheet.
 15. The method according to claim 1,wherein the substrate comprises a wood-based board, a particleboard, athermoplastic board, a plywood, a lamella core, a veneer layer, a sheet,or a non-woven.
 16. The method according to claim 1, wherein the firstlayer or the second layer comprises a resin impregnated paper sheet. 17.The method according to claim 16, wherein the first layer and the secondlayer comprise a resin impregnated paper sheet.